<?php
$arr=array(12,100,55,66,99);

$arr1=array("a","b","c","d","e");
function mymax($arr){
    $len=count($arr);
//    $max=$arr[0];
    $maxi=0;


        for($k=0;$k<$len-1;$k++){
            if($arr[$maxi]<$arr[$k+1]){
                $maxi=$k+1;
            }
        }

    return $arr[$maxi];

}

print_r(mymax($arr));
//print_r(count($arr));
echo "<hr>";
foreach($arr as $v){
    echo $v;
    echo "<hr>";
}

echo "<hr>";
function pj($arr,$arr1){
    $len=count($arr);
//    echo $len;
    $arr3=array();
    if($len==5){
        for($i=0;$i<5;$i++){
            $arr3[]=$arr[$i];
            $arr3[]=$arr1[$i];
//            echo $arr[$i+1];
        }
//        return $arr3;
        var_dump($arr3);
    }

}
pj($arr,$arr1);
//var_dump();